Ship hull having adjustable bow bulb



United States Patent [72] Inventors Robert S. Boston, 22 Shasta Court,

San Francisco, Calif. 94080; David J. Seymour, 680 Beach St., San

Francisco, California 94109 [21] Appl. No. 753,507 [22] Filed Aug. 19, 1968 [45] Patented Nov. 17,1970

[54] SHIP HULL HAVING ADJUSTABLE BOW BULB [56] References Cited UNITED STATES PATENTS 3,180,299 4/1965 Takao lnui 114/56 FOREIGN PATENTS 1,244,170 9/1960 France 114/56 Primary Examiner-Andrew H. Farrell Attorney-Emory L. Groff and Emory L. Groff, Jr.

ABSTRACT: A ship hull has an adjustable bulb carried at the bow thereof, the bulb being selectively movable in a fore and aft direction relative to the hull. The bulb can be moved from a retracted position to an extended position or to various intermediate positions between a retracted and extended position dependent upon the operating conditions of the associated ship.

, no 70 40 i E 72, a 74 52 e4. r 58 g i V 19 +36 I ll 1 M 56 5o J 32 Patented Nov. 17, 1970.

Sheet 1 0:2

MON OOH N IN vars ROBERT 5.50510 DAVID J. SEYMOUR ATTORAEY SHIP HULL HAVING ADJUSTABLE BOW BULB BACKGROUND OF THE INVENTION It is well known that a limiting factor concerning a ships speed or economy of operation is the resistance to motion caused by friction and by the waves resulting from the hull design. Accordingly, ships have been provided with a bulb at the bow of the ship to create a waveform which is roughly the reverse of that created by the ship and which has a counteracting effect on the bow wave which would be formed in the absence of such bulb.

Many designs have been proposed for so-called bulbous bows," these type of bows having a common characteristic in that they all have a bulb which protrudes a considerable distance forward of the stem of the ship as well as having a lateral extension outboard from the center line of the ship.

Prior art bulbous bow constructions include a bulb portion disposed in fixed relationship relative to the fore and aft direction of the associated hull. Accordingly, known bulbs present a number of problems and disadvantages under certain operating conditions such as anchoring, docking, low speed, ballast conditions, heavy weather and so forth.

Bow bulbs are commonly employed with relatively high speed ships. The bulbs are quite efficacious when the ship is operating at high speed, but the bulb serves no useful purpose at low speeds. In some instances, the protruding bulb is actually a disadvantage. For example, when anchoring a ship, the bulb may be damaged when letting go bower anchors. Furthermore, the bulb often suffers chafing damage from chain anchor rodes. Such protruding bow bulbs are also often damaged when docking ships in close quarters such as in turning basins and berths.

Additionally, protruding bow bulbs often receive pounding" and slamming damage in pitching during heavy weather conditions due to severe wave action. Conventional bow bulbs are developed for maximum efficiency at designers waterline and are adapted to be partly effective at all drafts, whereby'maximum efficiency at any particular operating condition is highly unlikely.

SUMMARY OF THE INVENTION In the present invention, the ship hull carries an adjustable bow bulb which is movable in a fore and aft direction relative to the hull and which can be adjusted from a retracted position to an extended position and to any intermediate position between the retracted and extended positions.

The nose or rounded forward portion of the bulb may be spherical or any shape desired to meet hydrodynamic requirements of the hull. The remaining portion of the bulb may be substantially cylindrical with its axis generally parallel to the center line of the associated ship.

Means is provided for selectively extending or retracting the bulb, and the bulb when fully extended represents the optimum design form for a ship operating at full-load and topspeed condition. The fully retracted position of the bulb as well as the various intermediate positions thereof cover a wide range of operating conditions.

For example, when anchoring, docking or in heavy weather operating conditions, the bulb may be fully retracted. On the other hand, the bulb may be extended to various positions intermediate the fully retracted position and the fully extended position whereby higher efficiency at any draft or trim condition can be obtained through adjustment of the position of the bulb.

When used for example on a merchant ship such as passenger, cargo, tankers, bulk carriers and miscellaneous types, the bulb may be fully extended under normal sea conditions at full load and full speed of the ship. In ballast or intermediate conditions at sea, the bulb may be disposed at a position somewhat less than fully extended. In heavy weather at sea, the bulb may be extended only slightly from its retracted position. On the other hand, when in port where no requirement exists for a bulb from either a hydrodynamic or hydrostatic standpoint, the bulb can be fully retracted to avoid damage to the bulb or to other ships and obstructions.

In modern day high-speed tugboats can also utilize the present invention wherein the bulb can be extended for highspeed operation and retracted under maneuvering and lowspeed towing or pushing conditions.

When utilized on oceanographic ships, the bulb may be provided with windows or viewing ports for observation purposes as well as for hydrodynamic effect. In such a case, the bulb can be fully extended for bottom viewing and then subsequently retracted at low speeds or in port to protect the windows or viewing ports carried by the bulb.

In a naval vessel, the same advantages as set forth hereinbefore would be obtained particularly at flank speed where the speed length ratio of the ship exceeds 1.0. The bulb may also be employed for carrying sonar gear, and the bulb can be completely removed with the sonar gear for ship repairs or replacement by another unit when required.

The adjustable bow bulb of the present invention can be compared with a controllable pitch propeller at the stern of the ship which can be regulated to obtain optimum pitch under all conditions of the vessel loading, trim and sea conditions. There is also the possibility of controlling both the position of the bow bulb and the propeller from a common com mand source to ensure that the vessels resistance forces and propulsion thrust are maintained at a balanced optimum.

When a vessel having a bulb according to the present invention is traveling in ice, the bulb can be retracted for protection. Additionally, when such a vessel is passing through locks with minimal dimensions, the bulb may be retracted-so that the vessel will fit within the locks retracted length. The retractable bulb of the present invention may also be employed where stern bulbs are used with many of the same advantageous features.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view ofa ship having an adjustable bow bulb according to the present invention;

FIG. 2 is a somewhat schematic view illustrating the adjustable bow bulb of the present invention along with the operating control means therefor;

FIG. 3 is a view similar to FIG. 2 illustrating a modified form of the invention; and

FIG. 4 is a sectional view taken substantially along line 4-4 of FIG. 3 looking in the direction ofthe arrows.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings wherein like reference characters designate corresponding parts throughout the several views, a typical sea-going ship is indicated generally by reference numeral 10 and includes a hull 12 having a bow 14. An adjustable bow bulb indicated generally by reference numeral 16 is carried by the lower portion of the bow below the waterline of the ship so that the bow bulb is submerged during operation of the ship.

Referring now to FIG. 2 of the drawings, the details of construction of the adjustable bow bulb and the operating means therefor are illustrated. The ship includes an outer shell 20,

and the bow bulb includes a rounded forward end 30 which may define a portion of a spherical surface and which joins with a substantially cylindrical main body portion 32 terminating in an end wall 34 from which extends a lug 36.

The bow bulb is supported within a chamber defined by a generally cylindrical support means 40. A guide and bearing means 42 is carried by support means 40 and is secured in place by means of screws 44. This bearing may typically be formed of laminated phenolic, hard rubber, bronze or the like so as to support the cylindrical main body portion of the bulb for fore and aft movement relative to the ship. A grease connection 46 is provided for lubricating the bearing.

It should be understood as illustrated in FIG. 2 that the orientation of the components is such that the bulb is movable in a fore and aft direction substantially parallel with the center line of the hull. The bulb is shown in full lines in this figure in its fully retracted position, and the phantom lines illustrate the fully extended position of the bulb.

The aft wall 50 of support means 40 carries a cover portion 52 which in turn supports a hydraulic ram means indicated generally by reference numeral 56. This ram means includes a piston rod 58 which is operatively connected with the lug 36 previously described by a pin 60. It is apparent that extension or retraction of the piston rod within the hydraulic ram cylinder 64 will result in extension and retraction of the bulb operatively connected with the piston rod.

A reversible constant delivery hydraulic pump 70 is connected with opposite ends of the ram cylinder 64 by means of conduits 72 and 74. A suitable electrical connection indicated by reference character 76 connects the pump with an operating means indicated by reference numeral 78 including a lever 80, this operating means being disposed at the bridge of the ship whereby operation of the pump 70 may be remotely controlled through a conventional selsyn system. As illustrated, lever 80 is in the retracted position which causes the pump 70 to move the bulb into its fully retracted position.

A pair of conduits 84 and 86 extend from opposite ends of the hydraulic ram cylinder 64 to opposite ends ofa position indicator 88. An indicator member 90 is movable within the in dicator means 88 in accordance with the position of the piston of the hydraulic ram means so as to indicate the position of the hydraulic ram means and accordingly the position of the bulb. This indicator means may be positioned at the bridge of the ship so that the position ofthe bulb can be readily determined.

The forward end of support means 40 is enlarged at 100 to provide an annular chamber within which is disposed a seal means 102. This seal means comprises a resilient doughnutshaped bellowslike member carrying a flexible sealing member 104 at the inner periphery thereof. An annular retraction spring 105 is disposed within the seal means 102 for insuring that the seal means will be retracted from the outer periphery of the bulb when air pressure is released from the seal means 102. This doughnut-shaped sealing means may be selectively inflated for urging portion 104 into tight sealing engagement with the outer periphery of the bulb.

The seal means is inflated through a conduit 106 which is connected with a selectively operable two-way valve 108 adapted to connect conduit 106 with either of conduits 110 and 112. The two conduits 110 and 112 are connected with a manifold 116 which in turn is operatively connected with a conduit 118 leading to a suitable source of air under pressure. A first control button 120 is provided, and when this button is depressed, conduit 110 is disposed in communication with conduit 118 so that air under pressure enters conduits 110. The valve 108 may then be selectively disposed so that conduit 110 is in communication with conduit 106, whereby the seal means is inflated and moved into tight sealing engagement with the bulb.

On the other hand, when it is desired to release the seal means from engagement with the bulb when the bulb is to be selectively adjusted in a fore and aft direction, valve 108 is moved to a position so that the conduits 106 and 112 are disposed in communication with one another. A further control button 122 is provided in manifold 116, and when this control button 122 is depressed, conduit 112 is disposed in communication with an exhaust outlet 124 which allows the air pressure within the seal means to exhaust to atmosphere, thereby deflating the seal means.

A further control button 130 is provided in the manifold 116 for selectively connecting a conduit 132 in communication with the conduit 118. This conduit 132 is also in communication with the chamber defined within support means 40.

The seal means normally provides a substantially watertight seal with the bulb. However, the seal means is released when the bulb is adjusted in the fore and aft direction whereupon a certain amount of water may leak into the chamber defined within support means 40. When the seal means is subsequently moved back into tight sealing engagement with the bulb, the water within support means 40 may be blown out by introducing air pressure through conduit 132. The water within support means will be blown out to sea through a water drain vent pipe 134.

A scraper and guard means is indicated generally by reference numeral 140 and comprises an annular member which may be formed of a relatively resilient metallic substance. This scraper and guard means includes a forwardly tapering portion 142 terminating in a relatively sharp edge 144 which is adapted to snugly engage the outer periphery of the bulb when in its extended position. This sharp edge will serve as a barnacle scraper for scraping off barnacles and other foreign matter which may accumulate on the outer surface of the bulb.

Assuming that the components are in the operative position shown in FIG. 2 wherein the bulb is in its fully retracted position and it is desired to extend the bulb into an extended position, valve means 108 and control button 122 will be operated to release the air pressure within the seal means 102 so that it will retract away from the bulb.

Lever is then moved from the release position shown in a clockwise direction to the extended position whereupon pump 70 will be operated in such a manner as to cause the bulb to be extended. When the bulb has reached the desired degree of extension, lever 80 may be moved to the intermediate offposition whereupon the bulb will be retained in the selected position. The indicator means 88 will indicate to the operator when the bulb has reached the desired operative position.

When the bulb is disposed in the desired adjusted position, valve 108 and control button are operated to again move the seal means into operative sealing position. Control button may then be operated so as to blow out any water which may have accumulated within the support means 40 during the foregoing operation.

Referring now to FIGS. 3 and 4 of the drawings, a modified form of the invention is illustrated. A large portion of the structure of this form of the invention is substantially identical with that previously described, and accordingly similar parts have been given the same reference numerals primed.

The principal difference in this form of the invention lies in the particular construction of the bulb and the means for moving the bulb fore and aft of the associated hull.

In this form of the invention, the bulb is indicated generally by reference numeral and includes a rounded forward end 152 and a substantially cylindrical main body portion 154 ex tending aft thereof. A central tubular portion 156 is mounted concentrically within the body portion 154 and is interconnected therewith by a plurality of spaced annular ribs 158 having lightening holes 160 formed therethrough. A plate 162 of annular configuration is fixed to the aft ends of portions 154 and 156.

A bronze nut portion 166 is carried by the aft end of the tubular portion 156 and is internally threaded for engagement with the operating means hereinafter described.

A pair of flat bars 170 and 172 are supported at diametrically opposite inner portions of the support means 40' and are disposed within correspondingly shaped notches formed in a radially outwardly extending peripheral portion of the annular plate 162. The interengagement of these bars and notches serves to guide fore and aft movement of the bulb and to prevent rotation of the bulb relative to hull.

A support means is carried by the rear wall 50' of support means 40, and a bronze bearing 182 is mounted within the support means for a purpose hereinafter described. A grease connection 184 is provided for providing grease to the bearing and to the shaft supported within the bearing.

In this form of the invention, the means for operating the bulb includes a hydraulic motor 190, although an air motor may also be employed for this purpose. This hydraulic motor is operated by the pump 70 which in tum is controlled by the lever 80' of the control means 78 as in the previously described form of the invention.

A shaft 192 isdriven by the hydraulic motor 190 and includes an outer reduced externally threaded portion 194- which is threaded within the nut 166 operatively connected with the bulb. Since the bulb cannot rotate due to the interengagement of bars 170 and 172 with the notch portions of plate 162, rotation of the shaft portion 194 in opposite directions is adapted to cause the bulb to extend or retract as will be apparent.

In order to remotely indicate the position of the bulb, a counter mechanism indicated generally by reference numeral 198 is operatively associated with the shaft of the hydraulic motor 190. This counter is operatively associated through a connection 200 with an indicator means indicated generally by reference numeral 202 having an indicating member 204 disposed therein whereby the position of the bulb may be indicated at the bridge of the ship.

it is apparent that the operation of this form of the invention is substantially identical to that previously described insofar as the various controls are concerned, the only major difference being that this form of the invention is screw operated whereas the previously described form of the invention is hydraulically operated.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not bulb may be selectively moved to a retracted position, an extended position or an intermediate position between the retracted and extended positions.

5. Apparatus as defined in claim 1 wherein said bulb has a rounded forward end and a substantially cylindrical main body portion.

6. Apparatus as defined in claim 1 including seal means engageable with said bulb for providing a substantially watertight seal therewith.

7. Apparatus as defined in claim 6 wherein said seal means is disposed in surrounding relationship to said bulb and is engageable with the outer periphery thereof.

8. Apparatus as defined in claim 6 wherein said seal means is adjustable so as to be selectively moved into tight sealing engagement with said bulb or retracted from such tight sealing engagement with the bulb.

9. Apparatus as defined in claim 1 including guide means supported by said, bow, said bulb being movably supported and guided by said guide means for movement in a fore and aft direction relative to the hull.

10. Apparatus as defined in claim 9 wherein the guide means supported by said bow comprises elongated means engageable with guide means on said bulb for preventing relative rotation of the bulb with respect to the bow.

restrictive, and since the scope of the invention is defined by the appended claims, all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents are therefore intended to be embraced by those claims.

We claim:

1. A ship hull including a bow, an adjustable bulb carried by said bow and movable in a fore and aft direction relative to said hull, and means for selectively adjusting the position of said bulb in a fore and aft direction relative to the hull.

2. Apparatus as defined in claim 1 wherein said adjustable bulb is disposed below the water line of said hull so as to be submerged in operation.

3. Apparatus as defined in claim 1 wherein said adjustable bulb is movable in a direction substantially parallel with the center line of said hull.

4. Apparatus as defined in claim 1 wherein said adjustable 11. Apparatus as defined in claim 1 including means defining a chamber carried by said bow, said bulb being movable into and out of said chamber, seal means for providing a substantially water-tight seal with said bulb as it moves in and out of said chamber, and blowout means for expelling fluid which ma accumulate in said chamber.

2. Apparatus as defined in claim 1 including a scraper means supported by said bow and engageable with the outer periphery of said bulb.

13. Apparatus as defined in claim 12 wherein said scraper means is of annular configuration and is of a resilient construction.

14, Apparatus as defined in claim 1 wherein said means for selectively adjusting the position of said bulb includes a hydraulic ram means operatively connected with said bulb, and means for remotely operating said hydraulic ram means.

15. Apparatus as defined in claim 1 wherein said means for selectively adjusting the position of said bulb comprises screw operated means operatively associated with said bulb, and means for remotely operating said screw operated means. 

